#define _CRT_SECURE_NO_WARNINGS 1
#include <stdio.h>

int main()
{
	int i, a[10],sum=0;
	float avg;

	for (i = 0; i < 10; i++)
	{
		scanf("%d", &a[i]);
		sum += a[i];
	}

	avg = sum / 10.0;
	printf("%.2f", avg);

	return 0;
}